高速列车制动盘材料的研究现状与展望

在国内外高速列车中,传统的制动盘材料主要包括铸铁、铸钢和锻钢,钢质制动盘的制备工艺成熟,性能稳定,但质量大,不能满足列车轻量化和向更高速度发展的需要;碳/碳纤维复合材料、铝基复合材料和陶瓷材料具有密度小、比热容大等优点,但要成功应用于高速列车制动盘仍有一些问题尚待解决;此外,简要介绍了制动盘材料的表面强化技术;最后,根据不同制动盘材料的优缺点,对我国制动盘材料的发展方向提出了一些建议。     

一种铝基复合材料制动盘用树脂基摩擦材料

研制了一种适用于铝基复合材料制动盘的树脂基摩擦材料,测试了其物理力学性能及摩擦磨损性能。结果表明：所研制的摩擦材料具有较好的物理力学性能,各项指标达到了相应的技术要求;与用于铸铁制动盘的摩擦材料相比,具有更高的摩擦因数,更小的磨耗,制动力矩曲线平稳,能更好地适应铝基复合材料制动盘。另外,台架试验结果表明：摩擦副的摩擦磨损性能能够满足200km／h高速列车的要求。     

不同摩擦副在MM3000型试验机和TM-3型台架机上的对比试验研究

在MM3000型试验机和TM-3型台架机上,在0.40-0.50MP制动压力、80-200km/h制动速度下,对比了不同摩擦副干态工况条件的平均摩擦系数与磨损量。结果表明:克诺尔铜基摩擦材料配对钢制动盘的摩擦副在MM3000试验机上的摩擦系数高于在TM-3台架机上的摩擦系数。相反,克诺尔铜基摩擦材料和金属陶瓷摩擦材料配对碳陶制动盘的摩擦副在MM3000试验机上的摩擦系数都低于在TM-3台架机上的摩擦系数。另外,不论是MM3000试验机,还是TM-3台架机,克诺尔铜基摩擦材料配对碳陶制动盘时的磨损量最大,克诺尔铜基摩擦材料配对钢制动盘时的磨损量居中,金属陶瓷摩擦材料配对碳陶制动盘时的磨损量最小。     

高速列车钢质制动盘锻造技术研究与发展

进入21世纪以来,随着列车速度的提高,列车动能的不断增加,为保证列车安全运行,高速列车需要有强大的制动力及黏着的复合制动系统,来保证良好的制动性能。纵观国内外高速列车技术,盘形制动装置是其基础制动方式的最佳选择。盘形制动装置依靠制动盘与闸片之间的摩擦获得制动力。国内外制动盘的种类繁多,曾应用过普通铸钢、普通铸铁及低合金铸铁等制动盘,由于列车速度的不断提高和轻量化要求,又相继研发了合金铸钢、钢质锻造、蠕墨铸铁和碳／碳纤维复合材料等制动盘。     

制动过程中闸片材料与制动盘温度关系试验研究

为探讨碳/陶制动盘与不同闸片材料的匹配性,对碳/陶制动盘分别与碳/陶复合闸片、铜基粉末冶金闸片和铁基粉末冶金闸片组成的摩擦副进行制动试验,研究了在制动过程中盘面各点瞬时温度、最高温度、闸片温度与制动工况的关系。结果表明：碳/陶制动盘与碳/陶复合闸片摩擦副温度及温度梯度均高于其他2种摩擦副,其温度梯度在低速制动时随压力的增加而明显增加,当制动速度较高时,温度梯度并没有随压力的增加而增加;对于碳/陶制动盘与铜基和铁基粉末冶金闸片摩擦副,随制动速度和压力的提高,盘面温度梯度变化不明显。原因在于材料导热性和起始摩擦因数决定了盘面的散热能力和制动功率,碳/陶制动盘与碳/陶复合闸片摩擦副因较高的起始摩擦因数以及较低的导热性,其制动功率高和散热能力低,导致盘面温度持续升高。     

高速制动工况下Cu基粉末冶金闸片材料的摩擦磨损性能

采用粉末冶金工艺,制得铜基摩擦材料;利用MM 1000Ⅱ型摩擦磨损试验机模拟列车实际工况条件,测试其摩擦磨损性能;用扫描电镜观察铜基摩擦材料表面磨痕,并分析其磨损机制。结果表明：一定制动压力下,铜基摩擦材料摩擦因数和磨损率均随着制动速度的增加先升高后降低,150 km/h时制动性能最好,250~300 km/h时制动性能最为稳定;制动速度一定时,随着制动压力的增加,摩擦因数先升高后降低,磨损率增大并趋于稳定,04 MPa时摩擦因数最大,08~10 MPa时制动性能比较稳定;铜基摩擦材料在高速制动工况下的磨损机制主要为磨粒磨损和疲劳磨损。     

高速列车制动材料高温摩擦磨损行为研究

高速列车制动盘制动时的高温摩擦磨损是导致制动盘失效的原因之一,针对高速列车制动材料,设计了4种不同温度梯度(25℃、200℃、400℃、600℃)的摩擦磨损试验。以制动闸片材料作为销试样、制动盘材料做为盘试样,进行销-盘式摩擦磨损试验。结果表明:25℃和400℃条件下都具有较高的摩擦系数,但是两种温度下的磨损类型不同;25℃条件下盘试样的磨损量和表面粗糙度均最大,以磨粒磨损为主,盘表面有明显犁沟现象;200℃条件盘试样表面平整,摩擦系数和失重量均最小,摩擦面有部分片状石墨起到润滑作用;600℃盘试样出现负磨损,氧化磨损和黏着磨损同时存在。     

铜铁合金复合摩擦材料高温摩擦行为

研究高速列车用铜铁合金复合摩擦材料的高温摩擦磨损性能。在PlintTE77高温疲劳试验机上对该材料进行高温摩擦磨损性能测试 ,并对摩擦后的磨痕进行了微观组织分析     

轮轨激励对高速列车轴装制动盘热-机耦合疲劳分析

为研究轮轨激励对高速列车轴装制动盘热-机耦合疲劳影响,建立高速列车制动盘动力学模型和三维瞬态热-机耦合有限元模型,对紧急制动工况下轴装制动盘振动特性和热-机耦合特性进行计算分析。结果表明,高速列车制动盘在垂向上的振动加速度值最大,横向上最小,且振动形式以制动抖动为主,在0～100 Hz范围抖动最剧烈;与无轮轨激励工况相比,有轮轨激励的轴装制动盘表面温度升高得既快又高,在散热时,温度下降也更快;摩擦面总体呈现三个环状温度分布,在摩擦半径中心处制动盘表面温度比两侧温度高,在三个不同的摩擦半径上,温度呈现梯度分布;有、无轮轨激励工况下制动盘表面的疲劳损伤和疲劳寿命的分布云图与制动盘表面的温度场分布情况基本一致,且热应力越大制动盘表面的疲劳损伤越严重,疲劳寿命越短。     

高速列车铜基粉末冶金闸片的制备及摩擦磨损性能

通过对材料配方进行优化设计,利用粉末冶金方法制备了高速列车用铜基粉末冶金闸片摩擦块,测试了其物理和力学性能;通过对闸片结构进行优化,组装出新型浮动式结构闸片,测试了闸片的摩擦磨损性能。结果表明:该闸片用摩擦块的剪切强度不小于7MPa;闸片的平均摩擦因数为0.37±0.05,平均磨损量为0.126×10~(-6) cm~3·J~(-1),满足国际铁路联盟对闸片摩擦磨损性能的要求;其制动性能也满足速度在350km·h~(-1)及以上高速列车的要求。     

含竹炭摩擦材料在高速高压下的摩擦磨损性能

研究竹炭作为摩擦组分对摩擦材料在高速高压条件下摩擦磨损性能的影响,以及竹炭与人造石墨混杂作为摩擦组分时摩擦材料的性能。结果表明,当竹炭质量分数为20%左右时,制备的摩擦材料在高压下具有较好的摩擦性能和较低的磨损率,但存在高速下低温摩擦因数偏高而高温摩擦因数偏低的缺点;将竹炭与人造石墨混杂作为摩擦组分时,材料在高速和高压条件下都具有很好的抗热衰退性和较低的磨损率,改善了含竹炭摩擦材料和含人造石墨摩擦材料在高速下摩擦因数不稳定的缺点。     

Effects of Zinc Borate and Fly Ash on the Mechanical and Tribological Characteristics of Brake Friction Materials

Friction materials based on several combinations of zinc borate (ZB) and fly ash (FA) were fabricated and characterized for their mechanical and tribological performance. The triboperformance of the friction materials was evaluated on a Chase friction testing machine according to the brake lining quality test procedure as per SAE J661. The composites were manufactured based on a nonasbestos organic-based friction material for an automotive brake system and contained typical ingredients for commercial brake friction materials. The composites had a fixed composition of 15 wt% resin, 15 wt% fibers, and 5 wt% friction additives. ZB and FA as fillers were added to the the raw materials mixture at a total fraction of 65 wt%. The results showed that ZB and FA contents have a significant influence on the mechanical and tribological properties of the friction composites. In particular, the composites containing 0–5 wt% ZB and 65–60 wt% FA showed better friction stability and improved fade resistance compared to those containing 10–35 wt% ZB and 55–30 wt% FA, whereas the composite with 5 wt% ZB and 60 wt% FA showed a maximum friction coefficient. On the other hand, the specific wear rate of the composites decreased with increasing ZB and decreasing FA contents. The morphologies of the worn surfaces as well as wear debris were analyzed by means of scanning electron microscopy.     

Effect of Matrix Alloying of Fe on Friction and Wear Properties of Cu-Based Brake Pad Materials

Abstract

Argon-gas-atomized Cu–Fe prealloyed powder was used to prepare Cu-based composites, and the effect of matrix alloying of Fe on microstructure and friction and wear properties of the brake pad material was systematically investigated on an MS3000 friction and wear tester. The results indicate that matrix alloying of Fe induces the precipitation of a uniformly distributed iron-rich phase at the interior of grains, the segregation of the iron-rich phase along SiO₂–matrix interface, and the formation of pearlite in the vicinity of the graphite–matrix interface, which favors the strengthening of copper matrix, improves interfacial bonding, and protects the third body. The prealloyed sample exhibits relatively high friction coefficient and enhanced friction stability, as well as reduced wear loss when the braking speed is lower than 200?km/h. At higher braking speed (>200?km/h), the breakage of the iron-rich phase leads to an unstable friction coefficient and high wear loss.     

Influence of Thermal Fatigue on the Wear Behavior of Brake Discs Sliding against Organic and Semimetallic Friction Materials

ABSTRACT

In this article, brake discs are exposed to high thermal stress, causing thermal fatigue damage. The aim of this work is to study the evolution of the wear behavior of brake disc materials, such as cast iron, chromium steel, and metal matrix composites, under the influence of thermal fatigue. The brake disc specimens are heated and then cooled rapidly. Then, wear tests are carried out using a pin-on-disc-type tribometer. Organic and semimetallic friction materials are used for all wear tests. The results show that thermal fatigue affects the structure of the contact surfaces of all of the disc specimens by increasing their roughness. Furthermore, the wear rate of the friction materials increased, except a reduction of the wear rate is noted for the semimetallic friction material rubbing against cast iron. Moreover, thermal fatigue has no significant influence on the coefficient of friction. The worn surface of the metal matrix composite sliding against semimetallic friction material is characterized by abrasive and adhesive wear mechanisms.     

石油钻机盘式刹车副材料的摩擦磨损性能研究

为提高深井石油钻机盘式刹车副的摩擦学性能和使用寿命,研制开发了新型刹车盘表面堆焊材料和无石棉刹车块摩擦材料,并通过变温摩擦磨损性能实验,研究了刹车副的摩擦学性能。研究表明,刹车副具有良好的变温摩擦特性和高温抗热衰退性能,高温下的摩擦因数比较稳定;刹车块和刹车盘的磨损率均随温度的升高而增大,但刹车盘表现出相对稳定的耐磨性能。载荷对刹车副的摩擦因数影响不大,变化比较平稳;刹车块和刹车盘的磨损率均随载荷的增大而增大,但刹车块表现出相对稳定的耐磨性。刹车副的摩擦因数随滑动速度的增加而增大,并趋向平稳;但速度对刹车块和刹车盘的磨损率影响不大,变化相对稳定。研制的刹车副材料能够满足石油矿场钻机作业的要求。     

制动摩擦副材质对其摩擦性能影响的研究

对有机石棉和半金属衬片材料与不同化学组分的灰铸铁制动盘（鼓）进行摩擦性能试验。分析了对偶材质对衬片磨损及摩擦系数的影响及衬片材质对制动盘（鼓）磨损的影响。提出了评定衬片材料的耐磨性必须标明对制动盘（鼓）的损伤及制动副材料的最佳选配问题。     

Advanced Friction–Wear Behavior of Organic Brake Pads Using a Newly Developed System

The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.     

摩擦副组合对摩擦磨损性能的影响

在1：1惯性力矩制动试验台上研究了两种不同石墨形态的铸铁制动盘与两种混杂纤维增强的酚醛基制动闸片配副时的摩擦磨损性能。结果表明，对于某一配方的制动闸片，使用灰口铸铁盘的摩擦副具有较高的摩擦系数，但制动盘表面温度较高，闸片磨损量较大；对于某一种制动盘，使用B配方制动闸片时，制动盘表面的温度较高，但闸片的磨损量较小；在所有四种组合中，B配方制动闸片与灰口铸铁盘配副的瞬时摩擦系数能够完全满足有关技术要求。     

纤维增强树脂基摩阻材料的摩擦学研究进展

综述了纤维增强树脂基摩阻材料的研究和发展，主要分析了树脂基体、增强纤维和填料以及温度和PV值对摩阻材料摩擦学性能的影响及作用机理，简述了摩阻材料磨损机理的研究现状和主要磨损类型。并提出了今后研究摩阻材料应重视的问题。     

铜基粉末冶金/Q235B摩擦副载流摩擦磨损性能*

磁浮列车中部分制动闸片在服役时一直处于受流状态,导致材料磨损加剧,影响闸片的服役寿命。为研究中低速磁悬浮列车制动闸片在受流工况下的摩擦磨损性能,以制动闸片使用的铜基粉末冶金材料和刹车盘使用的Q235B材料为摩擦副,研究不同制动速度下铜基粉末冶金/Q235B摩擦副的载流摩擦磨损行为。结果表明：无电流时随着滑动速度的增大,摩擦因数及磨损率整体呈现下降的趋势,载流时随着滑动速度的增大,摩擦因数整体呈现下降的趋势,而磨损率则整体呈现上升的趋势;无电流时磨损后的铜基粉末冶金材料表面覆盖着一层靛色的第三体层,该第三体层低速时主要以颗粒状为主,随着速度的增加逐渐被压实成连续致密状,高速时因黏着磨损加剧使得连续致密状第三体被破环,导致材料的摩擦因数和磨损率呈现反向增长的趋势;载流下磨损后的铜基粉末冶金材料表面出现了以机械磨损为主和以电弧烧蚀为主的2个区域,其中以机械磨损为主的区域依然是由靛色的第三体层组成,而以电弧烧蚀为主的区域表面则覆盖了一层金色熔融状物质,并且随着速度的增大,烧蚀区面积也逐渐增大。